The nature and extent of emotional processes associated with borderline personality disorder (BPD) remain unclear. Laboratory studies that have included objective psychophysiological indicators of emotion have failed to document the hypersensitivity and hyperreactivity described in clinical accounts and questionnaire and interview studies of BPD. Working from an emotional granularity perspective, which refers to the specificity in which individuals represent and experience emotions, the current study will attempt to elucidate the affective processes associated with BPD. BPD+ and BPD- participants will complete a series of laboratory tasks that will assess emotional granularity on three levels- physiological, applying labels to emotional experience, and semantic/conceptual structure of emotion language. The primary laboratory task will consist of participants viewing a series of images from the International Affective Picture System (IAPS; Lang, Bradley, & Cuthbert, 1999) and rating how the images made them feel while a number of psychophysiological indicators of emotion are measured. It is hypothesized that individuals with BPD will be less responsive to the arousal (intensity) dimension of the images leading to a less refined pattern of all or nothing responding. For a select number of IAPS images, participants will be asked to rate their affective reaction to each picture using 16 emotion-related adjectives. Using procedures developed by Feldman Barrett (2004), indices of the specificity in which individuals use labels to describe their experience will be derived. It is expected that BPD+ individuals will label their experience in a more global, less refined manner. Finally, a semantic similarities task will be employed to examine participants' structure of semantic/conceptual emotional knowledge. Furthermore, by including a state manipulation, a second aim of the study will be an additional test of the hypothesis that the affective dysregulation associated with BPD occurs in a context that triggers interpersonal schemas, such as the violation of maladaptive expectations about others' care and support. Relevance to Public Health: Individuals with borderline personality disorder (BPD) experience a range of life problems including unemployment, dysfunctional parenting and marriages, violence, and legal problems which drain limited public health resources. Research suggests that BPD is the most common personality disorder encountered in clinical settings, affecting 10% of psychiatric outpatients and 15-20% of psychiatric inpatients. Clearly identifying dysfunctional emotional processes associated with BPD will inform treatments for this costly condition and help decrease societal costs. [unreadable] [unreadable] [unreadable]